Dental casting-machine.



H. NHRA.

DENTAL CASTING MACHINE.

APPLICATION FILED SEPT. a. 19x 7.

1,283,859. Patented Nov. 5, 1918,

FlGiL 5 37 Z I V '73 47 5 $7 [7 2 06723 07 Hwruc ga Mira j j '6 6y HORAOIO MIRA, OE BOSTON;.MA.SSACHUSETTS.

v DEE'TAL CASTING-MACHINE.

Specification of Letters Patent.

Patented Nov. 5,1918.

Application filed September 6, 1917. Serial No. 190,064.

To all whom it may concern.

Be it known that I, HoRAoIo MIRA, a citizen of the Republic of Chile, residing at Boston, county of Sufiolk, Commonwealth of Massachusetts, have invented certain new and useful Improvements in Dental Casting- Machines, of which the following is a specification,

This invention relates to casting apparatus, and particularly to apparatus for making inlay castings for fillings and the like.

The object of my invention, broadly stated, is to improve and simplify existing apparatus of this class, particularly in respect to the instrumentalities for fusing the inlay and for forcing it into the mold. 7

According to my invention, the casting is fused in the depression made in the top of the plaster of Paris or other investment by means of an electric arc, the movable element of which is brought into effective relation to the casting, and afterward'automatically swung out of the way to permit a coinpressedair nozzle to be placed over the mold and the old forced down into the avity, the arrangement bein movement. of the nozzle to its position over the mold automatically causes the movable arc element to swing out of the way,-thus permitting manipulation of both instrumentalities by one hand and obviating the necessity of handling the intensely heated electric arc.

Another feature of my invention consists in the arrangement for automatically opening and closing the valve-controllin the dis charge of the compressed air into t e mold, according to the position of the delivery nozzle with relation to the mold, whereby the operativeis relieved of the necessity of manually manipulating any control for the compressed air source. c

A further feature of my invention consists in the arrangement for adjusting the effective length of the arc, whereby the intensity of the heat application may be varied according to the requirements of the pan ticular inlay being cast.

These and various other features which will appear more fully hereinafter are secured in the device of the present invention.

' The construction and operation of which together with a preferred embodiment thereof are disclosed in the following specification, illustrated in the accompanying drawings such that the and particularly defined in the appended claims. Throughout the specification and drawings like reference characters are correspondingly employed and in the drawings :v

Figure l is an end elevation, partiall in section, of a dental inlay casting mac ine in accordance with my invention,

Figs. 2 and 3 are side views thereof, partially in section, showing the successive operative positions of the arc and nozzle, respectively, and

Figs. 4: and 5 are respectivel a fragmentary plan view and a sectional elevation of the latching mount for the arc arm.

I have indicated at A a suitable base in which may be contained asource of compressed air B and upon which is mounted the mold C, the movable element D of the electric arc and the delivery nozzle E for the compressed air.

The compressed air source may be of any desired type and is here shown only diagrammatically. The delivery nozzle E is connected with said source by any suitable flexible connection, as the pipe 6. This nozzle includes a stem 7 having an axial bore' 8 into the upper end of which the pipe 6 delivers. The lower end of the bore 8 is forked as indicated at 9, the ends of the forks opening against the internal face of a sleeve 11 within which the stem 7 is slidable against the action of-a spring 7 confined between said sleeve and a shoulder 7 formed on said stem. The bore Sis normally sealed by a conical valve 10 fixed to the lower end of the. stem 7 and adapted to normally seat against a conical seat formed on the internalface of the sleeve 11. (See Fig. 3). Fast to the sleeve 11 is a suitably flanged head 12 which may be provided with a facing'of asbestos or other heat insulating material 13 andwhich is'adapted to be brought into sealing relationwith the plaster of Paris-or other investment 48 of the mold C. The head 12 and facing 13 are perforated as indicated at 12 to permit the passage of the ompressed air from the bore 8 into the mold cavity when said bore is open. Vvhen the head 12 is brought down against the mold, the stem 7 moves relative to the sleeve 11, compressing the spring 7 and carrying the valve 10 away from its seat, thus opening the bore 8; when the stem 7 is raised, the spring 7 holds down the head 12 until the valve l0 again finds its seat, thus closing the bore 8 whereupon the stem 7 and head 12 move together in the further lifting of the stem.

To effect this automatic opening and closing of the valve 10, the upper end of the stem. 7 is pinned at 15 to a frame 16, provided with .a handle 17, and. pivot-ally mounted at 18 to a tubular upright 19 rising from the base A. The frame 16 adjacent its pivot 18 is notched as indicated at 20 to receive a latch rod 21 which is slidably mounted in the tubular support 19 risin from the cover plate of the base A. The rod 21 extends through said cover plate and there engages one end of a latch release lever 22, pivoted at 23 to the under face of said cover plate. The opposite end of the lever 22 engages a slidable latch rod 24 extendin through said cover plate parallel to the rod 21 and guided in a suitable 11 )right 25 rising from said cover plate. The upper end of the rod 24 works against the under face of a dog 26 which is pivoted at- 27 to a boss 28 formed on arm 34 pivoted to a support 29 fastened to the cover plate of the base A, and suitably insulated therefrom as indicated at 30, the upper end of said support 29 being formed'with a locking notch 31 adapted to be engaged by the under face of the dog 26. The boss 28 is chambered to receive a coil spring 32 confined therein about a pintle 33 set through the support 29. Mounted to turn on the pintle 33 is a Suitably curved tiltable arm 34, the upper end of which is formedas a tubular holder 35 for the slidable sleeve 36 of the movable elementof the electric arc arm 34, the support 29 being provided with a: rigid extension 37 disposed under the tilting arm 34' and formed to support said arm 34 when said arm is in its non-eflective position. (See Fig. 2). i v I p I The sleeve 36 is adapted to be adjusted longitudinally of the holder35 to vary thev intensity of the heat application. As here shown, the usual carbon element indicated at 36 is clamped within the sleeve 36 by a clampj 38 adjustably held to the sleeve by a collar 39 and set screw 40, the'inn'er end of said element being received in a screw stem 41 threaded through the rear end of the sleeve 36, the stem 41 with clamp 38,

collar 39, and set screw 40 permitting the movable element 36 to beadjusted independently of the adjustment of the sleeve 36 and also providing for the removal of the element 36 for purposes of renewal.

,. The adjustment of the sleeve 36 may be effected in any desired manner. As here sho'wn, one face of the sleevev is provided with a longitudinal series of rack teeth 42 with which meshes a pinion 43 mounted on a transverse shaft 44 disposed over the.

sleeve and provided with an operating hub 45 whereby the pinion may be manually rotated. To protect the pinion 43, the holder 35 for the sleeve 36 may be formed with a of the depression 47 are carbon elements 51 which cooperate with the movable negative element 36 to produce the electric arc. The carbon pencil 36 which constitutes the negative element and the carbon elements 5l51 are respectively connected to corre- I Y spending poles in suitable power circuit.

The operation is as follows: The cavity 50 of the investment 48 having been modeled by the wax or other pattern,

and the gold or other metal to be fused having been placed in the depression 47, the fusing is effected by swinging the arm 34 on its pivot to bring the negative element 36 which has been properly adjustedto give the proper heat intensity, against the carbon elements 5l5l (see Fig. 1).. In this movement of the arm 34, the spring 32 is put under tension. When theinlay has been fused the handle 17 of the frame 16 is the rod 24. This lifts the latch 26 which is pivoted in the arm 34 out of engagement with the notch formed on the upper part of the support 29 to which the arm 26 is pivoted. This permits the spring 32 which has been compressed in swinging the arm 34' foward to expand and thus return the arm 34 to normal position,- and to subsequently position the compressed air delivery E over i. the mold C, as shown In Fig. 2 and in such positioning automatlcally opening the bore 8 to permit the air to pass therethrough into the depression 47 and force the fused charge through assage49 into the cavity 50 formed ,in the in stment 48. Specifically when the frame 16 1s brought down, the inclined walls of the notch 20 force the rod 21 clownwardly,,rocking the lever 22 on its pivot 23 and raisim the rod'24 thereby lifting the dog 26 suthciently to cause its notch 31 to clear the support 29,-whereupon the spring 32 tu ns, the arm 34 on its pivot 33 until said arm. rests upon the rigid underneath sup-( port provided for it by the extension 37. will, be evident, therefore, the'movable element; 36 is returned automatically and the operative is ,thus relieved of the trouble and delay in handling these parts.

ll'hcn the head 12 of the stem 7 contacts the investment. 48. the continued downward pressure applied to the stem by the handle, 17. will cause said stem to move down into the sleeve it a distance sul'licient to carry the valve It) wayt'rom its seat. thus openingthe bore 5. such downward movement being resisted by the spring T which is thus compressed so that when the stem 7 raised by the lifting ol the frame l said spring: will h ld down the sleeve-ll until the valve 10 again finds its seat. thus again sealing the bore S.

The air supply is therefore automatically opened and closed by and in the movement of the stem 7 to position. and the operatire consequently relieved of the necessity of manually manipulating any controls for the air supply.

While l have shown and described my invention as operating with compressed air. it will be understood that l may use any other gaseous or vaporous agent which when released over the mold will exert sullicient pressure to force the fused inlay into the pattern cavity.

li'hile the device in the-torm shown is particularly adapted tor use in dental work and is described with special reference to such it is obvious that my invention is applicable to any small casting work as in the ewelers" trade in either nnuiufin-turing or repairing.

Various modification in the form and coin struction of my device may obviously be resorted to it within the limits of the appended claims.

'What I therefore claim andd sire to se- .cure by Letters Patent. is:

l. in a casting machine. in combination. a mold. a movable pressure delivery having an effective and an ineffective position relative to said mold, a pivoted frame carrying said delivery, a pivoted electrical heating element having an effective and an incited tive position relative to said mold according to the position of said delivery, a latch for locking said heating element in effective position and released by the movement of the delivery to elt'ective position, a spring for moving" said heating; element to inei'tective position upon release of said latch, and an operative connection from said frame to said latch for releasing said latch upon a movement ofthe delivery to eti'ective position to permit said spring to move the heating unit to ineffective position.

'3. in a casting machine, in combination, a

mold. and a mo 'able heating unit including a rigid support. an arm mounted to turn on said support, a spring for turning said arm, a latch controlling said spring. a release for said latch to permit said spring to turn said arm to inellective position, and a heating element mounted on said arm.

3. In a casting machine, in combination. a inold. a pressure delivery having an efi'ec tive and an inetl'ective position relative to said mold. a movable heating unit including a rigid support. an arm mounted to turn on said support. a spring tor turning said arm to its ineffective position. a latch controlling said spring. a release for said latch operated by said pressure delivery in its movement to eti'ective position to release said spring and allow it to turn said arm to ineffective position. and a heating element mounted on said arm.

l. in a casting" machine. in combination, a mold. a stationary carbon element associated therewith. a movable carbon elen'icnt adapted to cooperate with said stationary element, and a support for said movableelement ineluding an arm lurnably mounted. a sleeve carried by said arm tor l'iolding said movable carbon element, and means for adjusting said carbonelement indepeiidently of the movement- 0]": said arm.

5. In a casting machine, in combination, a mold, a stationary -arbon element associated therewith, a nu able 'arbon element adapted to cooperate with said stationary element, and a support for said movable element including an arm turnably mounted, a spring for turning said arm in one direction, and an automatic release mechanism for said spring.

(3. In a casting machine, in combination, a mold. a stationary carbon element associated therewith, a movable. carbon element adapted to cooperate with said stationary element, and a support for said movable element including an arm'turnably mounted. a sleeve carried by said arm for holding said movable carbon element, rack teeth on said sleeve, and a pinion carried by said arm and meshing with said rack teeth for adjnsting said carbon element, independently of the movement; of said arm.

In testimony whereof l aliix my signature in presence of two witnesses.

HORACIO MIRA.

\Yitnesses:

Ylc'roma Lowonn, MARY P. ll 'o'rnnnseooN. 

